When Renzo Piano, the Italian architect, first stood on the roof of the old California Academy of Sciences building and looked around at the surrounding green of the park and the hills beyond, a vivid image of the new building came to him: he would lift up a patch of the park and slide the museum underneath! And that is essentially what he did.

The green roof on the Academy symbolizes that patch of parkland envisioned by Mr. Piano. A large, undulating expanse of green (2.5 acres), it feels something like a magic carpet that just happened to land and settle down over the domes and heating ducts of the new Academy. It is, of course, an energy-efficient means of insulation and a water-capturing feature that contributes to the sustainability quotient of the building. But it is also truly a living roof and it has been evolving and changing since it was planted in the fall of 2007.

It started with 9 native plant species, but now has 75 species and growing. The original plant species were all ground-hugging, giving the roof a more uniform appearance, like a real carpet . . . more architectural (perhaps more in keeping with the architect’s original vision). But now, with the addition of grasses, monkey flower, california fuschia and other plants that stick up, spiking and clumping, it is looking more like a garden . . . a little scruffy . . . real.

In fact, it has evolved into a fascinating outdoor exhibit and a living laboratory. Under the direction of staff at the Academy’s Naturalist Center, groups of citizen scientists are monitoring the roof on a regular basis, recording baseline data about the plants, birds and insects that live in the roof. To find out more about this project go to: http://www.calacademy.org/science/citizen_science/livingroof/

And while you’re on the roof you might also notice a square, bare plot of earth, roughly ten foot square, with no plants growing at all right now. This is a “succession plot,” a kind of earthen petri dish to monitor the “natural” succession of plants on the roof. The plot will be filled with biodegradable trays of sterile earth and watered along with the rest of the roof. High school students, under the direction of Dr. Frank Almeda, Senior Curator of Botany at the Academy, will keep track of plants that sprout and grow there. Will they be exotics, from seeds dropped by birds or the wind? Or native species, offspring from plants already growing on the roof? Will there be a battle for succession?

Wouldn’t it be great if the park at large could be a living laboratory like this, a place to experiment and learn about urban ecology, study the effects of climate change, monitor wildlife throughout the year . . . so many possibilities come to mind . . .